222 
ON SOME BEACHIOPODS AND A BIVALVE FROM HEATHCOTE. 
(By Fredk. Chapman, A.L.S., F.R.M.S.) 
The following fossils are comprised in a series collected by Prof. J. W. 
Gregory, D.Sc., F.R.S., from the older palaeozoic beds at Heathcote, which 
have been grouped with the Cambrian on the evidence of certain trilobite 
remains. 
The preservation of these fossils is such that it is not easy in all cases to 
determine the forms, even generically, with certainty, for they are chiefly 
represented either by internal casts or impressions of the shells. The matrix in 
which they are found is a fine reddish argillaceous or sandy material, and the 
fossils have to be isolated by carefully picking away the surrounding rock. 
The evidence derived from the present collection of fossils seems to make 
it fairly certain that we are dealing with an ordovician facies, with which 
are mingled a few forms of silurian affinities. 
By far the larger number of specimens may be referred to the genus Orthis, 
with its sub-genera Hebertella and Bilobites; but other genera are also present 
as Siphonotreta, Chonetes, Strophomena, and Rhynchonella ( Camarotoechia ?), 
as well as a small bivalve provisionally referred to Modiolopsis. 
The collection contained— 
Siphonotreta obovata , sp. nov.—Specimen 3 (figured). 
Siphonotreta discoidalis, sp. nov.—Specimen 22 (figured). 
Chonetes concinna, sp. nov.—Specimen 25 (figured). 
Strophomena flabelloides , sp. nov.—Specimens 7, 8, 9 (figured), 10, 11. 
Orthis fragments.—Specimens 1, 2, 12, 14, 16, 17, 18, 19, 20, 26, 30, 31, 
32, 35, 36. 
Orthis leviensis (?), Eth. fil.—Specimen 23 (figured). 
Orthis tenera , sp. nov.—Specimens 13, 27 (figured). 
Orthis (Hebertella) vespertilioides , sp. nov.—Specimen 21 (figured). 
Orthis (Hebertella) raristriata, sp. nov.—Specimen 28 (figured). 
Orthis (Bilobites) divaricata, sp. nov.—Specimens 5, 37 (figured). 
Rhynchonella (Camarotoechia?), sp.—Specimen 29 (figured). 
Modiolopsis (?) knowsleyensis, sp. nov.—Specimen 15 (figured). 
DESCRIPTION OF SPECIES. 
CLASS BRACHXOPODA. 
SIPHONOTRETA, DE VERNEUIL. 
Siphonotreta obovata, sp. nov. 
Plate XXI., Fig. 1. 
Ventral valve sub-oval, sub-acuminate posteriorly, broadly rounded at 
opposite border. Surface of valve high and well rounded anteriorly. Fora¬ 
men large, placed obliquely to the upper surface and close to the posterior 
margin ; area on each side of foramen much depressed. Surface of valve 
marked by numerous fine concentric lines. Greatest length of valve, 5mm.; 
width 4.5mm. 
This species is like S. unguiculata, Eichwald, in some respects, but is alto¬ 
gether broader ; the concentric markings are finer, and the foramen is set on a 
conspicuous prominence. No vestiges of spines were seen in this specimen. 
